Archive for the ‘Work File Only – Observer’s Challenge Reports’ category

NGC 7662 Planetary Nebula in Andromeda: November 2021 Observer’s Challenge Report #154

November 19, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

November 2021

Report #154

NGC 7662 Planetary Nebula in Andromeda

Sharing Observations and Bringing Amateur Astronomers Together

Final November .pdf report, click on the following link:

This is the observer’s challenge “Work-File” report: Used only for organization and editing. When all entries are received, a .pdf report will be issued by the 10th of December. And the link will be posted on this page.

Commonly called the Blue Snowball, the planetary nebula NGC 7662 dwells in the northern reaches of Andromeda. Its nickname springs from an article by Leland S. Copeland in the February 1960 issue of Sky & Telescope magazine. Copeland describes the nebula as “looking like a light blue snowball.” 

William Herschel discovered this nebula on October 6, 1784, with this 18.7-inch reflector. His journal entry reads: A wonderful bright, round planetary pretty well defined disk, a little eliptical [sic]; perhaps 10 or 12″ diameter. Another entry from October 3, 1790, endearingly states: My planetary nebula. A very beautiful object, with a vS [very small] star following; giving one the idea of a large Planet with a vS satellite. In his impressive new book, William Herschel Discoverer of the Deep Sky, NGC/IC researcher Wolfgang Steinicke credits William Herschel with 10 observations of NGC 7662.



NGC 6857: Emission Nebula – Cygnus: October 2021 Observer’s Challenge Report #153

October 13, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

October 2021

Report #153

Click on the following link, for the complete report:

october-2021-observers-challenge-_ngc-6857-1

This month’s target:

William Herschel discovered NGC 6857 on 6 September 1784. His handwritten journal for that date reads: A patch containing some nebulosity…irregularly long.

Heinrich d’Arrest writes of this object and his observation of it in his 1867 Siderum Nebulosorum Observationes Havnienses. My very loosely paraphrased English for the Latin text: Minute, faint; it is most probably a cluster. A 12th-magnitude star precedes it. – Rechecked shortly after: it was not so small; not all of the nebula is resolved, there is at least some cloudiness. I’m not surprised that this was missed by Rosse.

NGC 6857 is the brightest part of the larger, star-forming emission region Sharpless 2-100, which is a much more difficult visual target than NGC 6857. 

A 2010 paper by Manash Samal and colleagues in the Astrophysical Journal indicates that the main ionizing source at the center of NGC 6857 is the bright, massive star at its heart. This compact nebula is estimated to be approximately 28 thousand light-years away from us, and the star is thought to have a spectral type of about OIII. The most likely age of the nebula is in the vicinity of 1 to 2 million years. (Intro and object information by Sue French)

NGC 6823/Sh 2-86: Open Cluster/Emission Nebula in Vulpecula: September Observer’s Challenge Report #152

September 13, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

September 2021

Report #152

NGC 6823 & Sh 2-86, Open Cluster & Emission Nebula in Vulpecula

Sharing Observations and Bringing Amateur Astronomers Together

Observer’s Challenge Report: Final

September 2021 OBSERVERS CHALLENGE _NGC 6823 & Sh 2-86

This month’s target:

The nebula surrounding the open cluster NGC 6823 suffers an identity crisis. It’s not NGC 6820, as many sources claim, but rather a small knot of nebulosity 16 arcminutes in position angle 218 degrees (southwest by south) from the bright quadruple star at the cluster’s heart. 

Here is NGC/IC maven Harold Corwin’s explanation:

NGC 6820 is a small knot of nebulosity, roughly 1′ × 1′, perhaps a reflection nebula around a few young stars or pre-stellar objects. It is specifically NOT the much larger HII region Sharpless 2-86 as has been many times been claimed, nor is it the cluster Collinder 404 = OCl 122, though that may 

represent the stars involved with the nebula. Marth’s original observation with Lassell’s 48-inch reflector mentions only the nebulosity: “F, S, R, bM”. [Faint, small, round, brighter in the middle]

http://haroldcorwin.net/ngcic/ngcnotes.all 

The position of NGC 6820 is 19h 42m 27.9s  +23° 05′ 15″. Consider this a bonus object if you’d like.

Information above compiled by Sue French

Jaakko Saloranta: Observer from Finland (Pencil Sketch)

M57, Planetary Nebula in Lyra: August 2021 Observer’s Challenge Report #151

August 17, 2021

august-2021-observers-challenge-_m57Download


Roger Ivester: Observer from North Carolina

10-inch reflector, fairly bright with well defined edges, gray in color, oval shape with a center void.  Both the NW and SW sides are brighter with greater concentration.  The ring is much lighter, or thiner on the NW, and also on the SE, but more subtle.  A 12th magnitude star lies, so very close to the east of the ring.

3.5-inch Maksutov-Cassegrain telescope at a magnification of 146x, the ring nebula is presented as very dim, round but mostly featureless. The central void can be seen, but fairly difficult.  

102mm refractor at 175x, shows the ring as surprisingly bright on this night of exceptional viewing with sharp and well defined edges.  The center void can be seen, but only as a lighter round gray spot, within the ring. Bright star just to the east.

Pencil sketch below:  

NGC 5746, Galaxy in Virgo: June 2021 Observer’s Galaxy Report #149

June 14, 2021

Monthly Observer’s Challenge

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

June 2021

NGC 5746, Galaxy in Virgo

Sharing Observations and Bringing Amateur Astronomer’s Together

MONTHLY OBSERVER’S CHALLENGE

june-2021-observers-challenge-_ngc-5746Download

This month’s target

William Herschel discovered NGC 5746 on 24 February 1786 with his 18.7-inch reflector. His handwritten journal reads:” Extremely bright, much extended in the parallel, 8 or 9 arcminutes long, bright nucleus.”

A recent study by John Kormendy and Ralf Bender in the Astrophysical Journal presents NGC 5746 as a structural analog of our own galaxy. Both are “are giant, SBb–SBbc galaxies with two pseudobulges, i.e., a compact, disky, star-forming pseudobulge embedded in a vertically thick, ‘red and dead,’ boxy pseudobulge that really is a bar seen almost end-on.” According to the authors, the lives of these galaxies have been dominated by minor mergers and bar-driven evolution for most of the history of the universe. They place NGC 5746 at a distance of 26.7 Mpc (87 million light-years). https://ui.adsabs.harvard.edu/#abs/2019ApJ…872..106K/abstract

NGC 5746’s V(V_T) visual magnitude is 10.32 ± 0.13, and its surface brightness is 12.6. The galaxy’s visible extent through medium-size amateur telescopes under dark skies is in the vicinity of 7.4′ × 1.3′.

Globular Cluster, M3, NGC 5272 in Canes Venatici: May 2021 Observer’s Challenge Report #148

May 19, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

May 2021

Report #148

Messier 3 (NGC 5272), Globular Cluster in Canes Venatici

Sharing Observations and Bringing Amateur Astronomers Together

Introductio

This month’s target

Charles Messier discovered M3 on 3 May 1764 with a 3.5-inch refractor. The French text of Messier’s catalog in the Connaissance des Temps translates into English as: “Nebula discovered between the Herdsman and one of the Hunting Dogs of Hevelius; it does not contain a star, the center is brilliant & its light imperceptibly fades, it is round; when the sky is good, one can see it with a refractor of one foot [at the time, telescopes were generally described by their length]; it is reported on the Chart of the Comet observed in 1779. Mémoires de l’Académie of the same year. Reexamined 29 March 1781, still very beautiful.”

According to William H. Harris’ Catalog Of Parameters For Milky Way Globular Clusters,

http://physwww.mcmaster.ca/~harris/mwgc.dat , M3 resides 10.2 kiloparsecs (~33,000 light-years) away from us and 12.0 kiloparsecs (~39,000 light-years) from the galactic center. It shines with an integrated V-magnitude of 6.19, and the spectral type of the integrated cluster light is F6. Does its color look slightly yellow to you?

May 2021 Observer’s Challenge Complete Report: may-2021-observers-challenge-_m3-2

NGC 3226 and NGC 3227, Galaxies in Leo: April 2021 Observer’s Challenge Report #147

April 16, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

April 2021

Report #147

NGC 3226 & NGC 3227, Galaxies in Leo

Sharing Observations and Bringing Amateur Astronomers Together

This month’s target

William Herschel discovered this interacting galaxy pair on 15 February 1784 with his 18.7-inch speculum-metal reflector. His hand-written journal of the discovery reads: “Two nebulae almost close together. Perhaps 1½ or 2′ asunder, they are pretty considerable in size, and of a roundish form; but not cometic; they are very faint.” He also notes that on this night he first used: “A new, large object Speculum. It is very bright but not quite as distinct as my first, I shall however use it all the night.”

Together known as Arp 94, NGC 3226 and NGC 3227 are wedded in a gravitational dance 47.2 ± 0.2 million light-years away from us. Their complex dance has spawned a remarkable array of tidal tails as well as one tidal dwarf galaxy — a gravitationally bound condensation of gas and stars formed during the repeated encounters of the two parent galaxies.

The most recent journal paper on this captivating system can be perused here: https://www.aanda.org/articles/aa/full_html/2021/01/aa38955-20/aa38955-20.html

Observer’s Challenge Complete Report:

April 2021 OBSERVERS CHALLENGE _NGC 3226_NGC 3227

NGC 2685 – Galaxy In Ursa Major – March 2021- Observer’s Challenge Report # 146

March 18, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

March 2021

Report #146

NGC 2685, Galaxy In Ursa Major

Sharing Observations and Bringing Amateur Astronomers Together

march-2021-observers-challenge-_ngc-2685-2

Introduction

This month’s target

German astronomer Wilhelm Tempel discovered NGC 2685 in 1882 with an 11-inch refractor. Loosely translated, his discovery description reads: Good II-III; round; with a small star in the middle; stands 4′ south of a 10th-magnitude star. 

In the Hubble Atlas of the Galaxies, Allan Sandage states, “NGC 2685 is perhaps the most unusual galaxy in the Shapley-Ames catalogue.” While most astronomers would agree with this, there remain various opinions as to why. NGC 2685 is generally regarded as a polar ring galaxy wrapped in exterior hoops of gas and dust aligned nearly perpendicular to the plane of the galaxy’s lenticular disk. The rings may have been birthed by a merger and/or accretion event. A less touted viewpoint is that this galaxy is strongly warped, and the semblance of rings is merely the result of projection effects.

This perplexing galaxy lies roughly 50 million light-years away from us. As seen photographically, the unusual array of gas, dust, and resultant stars entwining the Helix gives rise to its name. The galaxy may also house a supermassive black hole. Sue French

NGC 1893 Open Cluster + IC 410 Emission Nebula – February 2021 Observer’s Challenge Report – Auriga #145

February 5, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

February 2021

Report #145

IC 1893 and IC 410, Cluster and Emission Nebula in Auriga

Sharing Observations and Bringing Amateur Astronomers Together

Introduction

This month’s target

John Herschel discovered the open cluster IC 1893 in 1827 with the 18¼-inch reflector at Slough in Buckinghamshire, England. His handwritten journal reads: “Rich, coarse, scattered and straggling. It more than fills the field. The stars are 9…15 magnitude.”  The engulfing nebula, IC 410, wasn’t discovered until 1892, when Max Wolf found some new extended nebulae on photographic plates taken with a 6-inch Voigtländer portrait lens. My paraphrased translation of the pertinent section of his discovery says: The ribbon-rich nebula shown on the plates around the star cluster surrounds the star BD+33 1023 [HD 242908] should also be new. It largely encloses the whole group.

The nebula is roughly 11,000 to 12,000 light-years distant, and the adolescent cluster within it is at least 4-million years old.

Complete Report: February 2021 OBSERVERS CHALLENGE _NGC 1893 and IC 410

IC 348 – Open Star Cluster Plus Nebula – Perseus – January 2021 Observer’s Challenge Report #144

January 2, 2021

Compiled by:

Roger Ivester, North Carolina 

&

Sue French, New York

January 2021

Report #144

IC 348 – Cluster plus Nebula in Perseus

Sharing Observations and Bringing Amateur Astronomers Together

This month’s target

During his term as the first director of Dearborn Observatory, Truman Henry Safford discovered IC 348 on December 1, 1866, with the observatory’s 18.5-inch refractor. Safford published his observation in a table of objects found at Dearborn in the years 1866–1868. The table uses the alphabet-soup notation common to the era, which decrypted means: very large, very gradually brighter in the middle, pretty bright. Additionally, a note below that section of the table describes the object as “A loose cluster with nebula.” The combo appeared in the First Index Catalogue.

IC 348 has the dubious honor of bearing two IC designations. Edward Emerson Barnard independently discovered the nebula in 1893, and it was placed in the Second Index Calalogue as IC 1985, without anyone tumbling to the fact that it was already in the previous IC catalog. Unlike Safford, Barnard didn’t note the existence of the cluster within the nebula. 

IC 348 is thought to be roughly 1000 light-years away and a youthful 2–3 million years old. It holds about 500 stars, with brightest being hot, blue-white stars on the main sequence. The cluster’s visual magnitude is 7.3. By Sue French

january-2021-observers-challenge-_ic-348